Ozone could replace sulfites as the preservative of choice in a new asthma-friendly approach to wine production. The approach could also help boost antioxidant levels in the final product. Mass-produced grapes often remain in storage for months, so are often exposed to sulfur dioxide to stop the rot. Such grapes are not used for wine production, of course, but sulfites are added to wine grapes to improve the shelf-life of the bottled product. However, sulfur dioxide and sulfites, while effective, can trigger allergic responses in some people and can worsen the symptoms of asthma for many wine drinkers with the condition.

Now, Francisco Artes and colleagues at the Technical University of Cartagena in Spain, and the Research Group on Quality, Safety and Bioactivity of Plant Foods in Murcia, have made a comparison of other preservative methods including a new technique that involves exposing grapes chilled at 0 Celsius to ozone. They found that ozone treatment was 90% as effective as sulfur dioxide. However, in contrast to sulfur dioxide treatment, ozone-treated grapes had up to four times the antioxidant content than untreated grapes.

The researchers are currently investigating why this fortuitous change should occur. It could be that the plant cells increase production of the antioxidants to protect themselves from oxidation by the ozone itself. Wine, and in particular red wine, is high in antioxidants. Compounds such as polyphenol, including resveratrol and catechins, are thought to endow wine with beneficial health properties. The scientific jury is still out on whether these perceived benefits actually outweigh the risks associated with the alcohol content. If the ozone approach can be adapted to preserve wine, side-step sulfur use, and boost antioxidants, then that may tip the scales.

J Sci Food Agric, http://dx.doi.org/10.1002/jsfa.2780

Chem Ind, 2007, Feb 12, p 11, http://www.chemind.org/CI/index.jsp

http://www.upct.es/gpostref/